Combustion apparatus



Sept. 18, 1934. w CORBETT 1,974,205

COMBUSTION APPARATUS Filed Jan. 26. 1932 2 Sheets-Sheet l INVENTOR we. w, emu/- Jmi outm- ATTORNEY Sept, 18, 1934. Lw. CORBETT COMBUSTION APPARATUS Filed Jan. 26. 1932 2 Sheets-Sheet INVENTOR W, QAFIW 3W, 21mm.

ATTORNEY Fatented Sept. 18, 1934 1,9743% v UNITED STATES PATENT OFFER 11,974,205 COMBUSTION APPARATUS Lawrence .W. Corbett, Belmont, Mass. Application January 26, 1932, Serial No. 588,882 2 Claims. (Cl. 110-36) This. invention relates to combustion apparawhich is, arranged to terminate a predetermined tus and to a method of combustion. I and short-distance above the conical grate. I

One object of the invention is to provide a novel have found thatfor most efficient and successful and improved combustion apparatus particularly operation of the combustion apparatus, it is de-.

5 designed for use in heating dwelling houses and sirable to varythe length and sectional size of for similar heating purposes where it is desired. the fuel discharge tube, and in the preferred emto burn solid fuel in an automatic manner. bodiment of the invention the fuel discharge tube Another object of the invention is to provide is removably supported within the hopper to a novel methodof combustion involving theconfacilitate, the substitution of different sizes of trol of the thickness of the fuel bed in a novel, fuel tubes when the apparatus is to be operated 65 economical and highly efficient manner. upon fuel. of different size.

With these general objects in view. and such Referring now tothe drawings illustrating the others as may hereinafter appear, the invention preferred embodiment of the invention, 10 repreconsists in the heating apparatus and in the sents a combustionchamber, 12 a conical grate,

15 method of combustion, and in the various struc- 14 a supply hopper for retaining the supply of 70 tures, arrangements and combinations of parts the solid fuel and from which the coal may hereinafter described and particularly defined in be discharged'onto the grate through a discharge the claims at the end of this specification. tube 16. Provision is made, as will be described,

In the drawings illustrating the preferred eme for rotating the grate d for S pp y he p ibodiment of the invention, Fig. 1. is a vertical maryair through the grate for maintaining com- 75 sectional view of the improved heating apparabustion, and during the operation of the appatus; Figs. 2 and 3 are sectional diagrammatic ratus a conical incandescent bed of fuel ismainviews illustrating portions of the heating appatained upon the grate in an automatic manner so ratus under different conditions of operation; and long as a supply of fuel is maintained within the Fig. 4 is a side elevation of the lower portion of supply hopper 14. I have found that most suc- 80. the machine illustrating the mechanism foropcessful and efiicient operation of the apparatus crating the grate. dependsto some extent upon the relation be- The present invention contemplates a contween the size of the discharge tube 16 and the disstruction of heating apparatus which is designed tance of the end of the tube from the upper porto enable the commercial solid fuels now upon tion of the conical grate, and I have found it the market such as the commercial grades of andesirable to vary the distance from the end of the thracite and coke to be burned in a manner which discharge tube 16 to the top ofthe grate in prois automatic for substantial lengths of time, as portion to the size of the lumps of particles of the for example a week, thereby reducing to, a minifuel, it being understood that the larger the pieces 35 mum the attention required and enabling. the of fuel, the greater the distance in order to maindwelling house to be heated in a satisfactory,safe tain a given output fromthe, apparatus. It has and economical manner. In the preferred em: been found that the rate of combustion is probodiment of the. invention the combustion or portional to the size of the pieces of the fuel, and heating apparatus is provided with a conical that the larger the individual pieces, the longer 40 grate supported for rotation within a combustion time isrrequired for burning. and consequently chamber, and provision ismade for feeding the withthe larger sizes of fuel a thicker fuel bed is fuel from a supply hopper preferably 1 onthe needed v thanwith the smallersizes. In, the illusoverfeed principle to the upper portion of the trated-apparatusthe flowjor discharge of the fuel grate. Airfor supporting combustion is supplied from the hopperthroughjthe discharge tube 16 .45 through the grate and throughthefuel bed, and is-controlledbyl the fuel bed itself, and in order to 1 provision is made for automatically moving the provide a thicker fire, the sectional size of the coal grate so that during continued combustionand tube should be varied when it is desired to use in the operation of the apparatus, the fuel gradudifferent sizes of fuel. In the illustrated appaally traverses down thegrate tobe discharged as ratus the discharge tube 16-is provided with a .50 ash over the periphery or base thereof. In order flange 21 designed to rest upon an annular shoul- 10 to adapt the apparatus for most efficient. and der 23' surrounding the opening 25in the bottom successful operation upon fuels of various size, the of the hopper, so -that when it is desired to alter apparatus is preferably provided with a removthe thickness of the fuel bed or the distance from able fuel discharge tube, arranged to project into the end of thedischarge tube to the conical grate,

the combustion chamber, and the lower end of these results may be conveniently accomplished portion of the inner wall is provided with ribs for cooperation with the roatry grate in grinding ash and such clinker as may be formed. The

upper surface of the skirt 32 is spaced from the lower portion of the inner wall of the coriibiistio'n chamber to form a throat or constricted passage indicated at 38. v u A u The conical grate 12 is, as herein shown; made up of a plurality of sections, and eachsection is provided with depending lugs 4'7 which cooperate with recesses in the next succeeding section to lock the sections together and to space one section a short distance from the next lower section so as to provide a series of downwardly and outwardly extending air channels 49 through which the primary air may be caused to pass through the fuel bed supported upon the grate. The lower section of the grate is bolted or otherwise secured. to a ring 43 having a ring gear 44 cooperating with a driving pinion 45 secured upon the end of a drive shaft 46 rotated through suitable mechanism, as will be described. The grate is supported on a series of ball-bearings 50 within a raceway formed by cooperative surfaces 57', 58 of portions of the lower section of the grate and ring 43 respectively, and the remaining sides of the raceway are formed by an angular recess 7 in a supporting ring 59 mounted upon the frame, as shown. The skirt 32 projecting from the lower section of the grate is provided with a downwardly turned lip 60 exthe operation of the apparatus the air under pressure from within the closed air chamber 66 passes through the narrow air passages 49 between successive sections of the grate to supply 'air for the combustion of the fuel. The construction of air pressure chamber 66 formed within the grate and burner pot serves to assist in preventing the entrance of ash or dirt into the bearings 50 by reason of the pressure through the bearings and outwar'dly under the projecting skir't.

During the operation of the apparatus, provision is made for rotating the grate, and as herein shown, the driving shaft 46 upon which the driving gear 45 is mounted, has affixed to its outer end a ratchet 70 with which a pawl '72 cooperates to advance the ratchet and consequently to effect rotation of the conical grate when the *pawl is advanced. The pawl is carried upon the top of a pawl arm 74, as best shown in-Fig. 4, which is connected to an arm '76, the latter being connected by a link 78 toa crank '80. The crank 80 is arranged to be revolved from an electric motor 82 through the medium o'fa reduction gearing 84 of any usual or preferred-form now upon the market. Provision-is made for controlling the effective throw of the pawl 72 to control the extent of grate movement at each revolution of the crank 80, and as herein shown, a shield member 84 pivoted upon the shaft 46 is arranged to be moved relative to the pawl so as to slide under a pin projecting from the pawl to maintain the nose of the pawl disengaged from the teeth of the ratchet for the desired portion of the normal stroke of the pawl to thereby prevent it from picking up any desired number of teeth. The pivoted shield is preferably connected to acontrol link 86 running from a thermostat or from a manual control.

In order to supply fuel to the conical grate to maintain a substantially uniform bed of fuel thereon, as herein shown, a bulk supply of fuel is stored within a fuel reservoir 1 1 located above thegrate in a position from which the fuel may automatically flow onto the grate by gravity. The flow of the fuel is controlled by the rate of consumption of the fuel bed in cooperation with the ash discharged therefrom and as longlas fuel remains in the hopper a substantially uniform fuel bed is maintained upon the grate. During the combustion sufficient air is supplied through the fuel bed to maintain practically the entire length of fuel bed incandescent, and the ash resulting from the combustion gradually slides and works downwardly toward the restricted throat or passage between the skirt 32 and'the dead ring 34 preparatory to being forced over the skirt to drop into the ash-pit where it may conveniently be caught in a removable ash receptacle 92.

Provision is also preferably made for effecting relative displacement or movement of the upper grate section 27 with relation to the remainder of the grate, and for this purpose the upper section 2'7 of the grate is mounted independently of the remainder of the grates upon the upper end of a post '75 aflixed to theburner pot so as to permit the upper grate section to rotate about the axis of the post 75. The next lower of the grate sections 26 is provided with a slot 73 of the shape illustrated and within which a pin 80 depending from the upper grate section 27 is adapted to ride, so that during the rotary movement of the main body of the grate about its own axis, the upper grate section 27 is moved by the engagement of the walls of the slot 73 with the pin 80. Thepost is mounted at one side of the axis of the conical grate, and with this construction, as the conical grate is rotatedthrough the driving mechanism previously described, the upper grate section is caused to be displaced with relation to the main body of the rotating grate.

:In Figs. 2 and 3 I have illustrated diagrammatically the differences in the sectional size of the fuel discharge tube 16 and also in the distance at which the tube is arranged to terminate in order to enable the thickness of the fuel bed to be controlled and varied in order that the apparatus may operate with maximum eiiiciency. As above stated, during the 'operation of the apparatus, fuel is fed through the discharge tube 16 onto the topof the conical grate and the latter is slowly rotated during combustion to effect the gradual movement of the burning fuel bed down the grate. The ash is discharged from the base of the grate substantially as fast as it accumulates in the lower portion of the fuel bed, and-in accordance with'the present method either the sides of the fuel discharge tube 16 or the distance of the tubefrom the top of the fuel bed, or both,=may be varied to insure the maintenance of a predetermined thickness of fuel bed depending upon the size -'of the fuel in order that the apparatus may operate with maximum efficiency to maintain a substantially incandescent cone of fuel upon the grate at all times during combustion except during bank fire periods.

While the preferred embodiment of the invention has been herein illustrated and described, it will be understood that the invention may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is:-

1. A combustion apparatus for effecting substantially complete combustion of solid fuel such as coal having, in combination, a combustion chamber, a conical grate rotatably supported within the chamber provided with openings therein of such character as to permit the passage of air therethrough and to prevent the passage of ash therethrough, fuel supply means including a hopper for containing a bulk supply of the fuel positioned immediately above the grate provided with a downwardly inclined bottom having an opening positioned above the apex of the grate and a fuel discharge tube extending downwardly from the bottom of the hopper to within a short distance of the top of the grate, said fuel discharge tube being supported at its upper end upon the walls of the hopper surrounding said opening therein and capable of being removed by bodily movement upwardly through said hopper whereby to enable fuel discharge tubes of different diameter and length to be conveniently installed, means for passing sufficient air under pressure through the conical fuel bed supported upon the grate to eifect substantially complete combustion of the fuel, and power oper-- ated means for continuously and slowly rotating the grate during combustion periods to remove ash from the lower portion of the fuel bed substantially as fast as it accumulates therein whereby in cooperation with the agitating effect inv duced in the upper portion of the fuel bed by the engagement therewith of the fuel discharge tube, the fuel bed is progressively caused to pass down the grate and during the entire combustion period is continuously and automatically maintained at incandescence.

2. A combustion apparatus for effecting substantially complete combustion of solid fuel such as coal having, in combination, a combustion chamber, a conical grate rotatably supported within the chamber provided with openings therein of such character as to permit the passage of air therethrough and to prevent the passage of ash therethrough, fuel supply means including a fuel discharge tube extending downwardly to near the apex of the grate in a position to engage the fuel bed thereon, and means for supporting the fuel discharge tube to permit replacement thereof without dismantling the apparatus, means for passing sufiicient air under pressure through the conical fuel bed supported upon the grate to effect substantially complete combustion of the fuel, and power operated means for continuously and slowly rotating the grate during combustion periods to remove ash from the lower portion of the fuel bed substantially as fast as it accumulates therein whereby in cooperation with the agitating efiect induced in the upper portion of the fuel bed by the engagement therewith of the fuel discharge tube, the fuel bed is progressively caused to pass down the grate and during the entire combustion period is continuously and automatically maintained at incandescence.

LAWRENCE W. CORBETT. 

